Common Ground
by lahmrh
Summary: An alien ambassador, tired of Spock and McCoy's constant arguing, lays down a decree; until they learn to get along with each other they will be unable to move more than ten paces apart. For McCoy it's his worst nightmare come to life, but when an emergency forces him and Spock to work together he learns his Vulcan nemesis might not be so bad after all. K/S, S&Mc friendship.


Author's Note: Written for the "Handcuffed/Bound Together" square on my trope_bingo card. Takes place post-TMP, during the second five-year mission.

**Common Ground**

Later, McCoy will insist it was all Spock's fault. All he did was make a _perfectly innocent_ comment about the Kalazan's embrace of emotion being a breath of fresh air, and the blasted Vulcan had to go and take it personally.

It's an old argument, one they've been having almost as long as they've known each other, and it doesn't take long for it to devolve into the usual sniping and veiled insults. McCoy almost forgets that they have company until he hears Kirk clearing his throat pointedly and turns to see the Kalazan ambassador watching them with narrowed eyes.

"Do they always argue so?" she asks Kirk.

McCoy feels his face heat a little, especially when Kirk seems to struggle for an answer. "Differing opinions can be an asset in our line of work," he replies eventually, and – in McCoy's opinion – a little weakly.

"Hmm." She studies Spock, then McCoy. "But surely seeing things from another's point of view is also important?"

"Of course," Kirk says immediately, "but-"

She holds up a hand. "On our world, those who cannot find a peaceful solution to their differences must go through the Test of Rukeer. I believe your crewmembers would benefit from doing the same."

"What does it entail?" Kirk asks.

The Kalazan ambassador shakes back her sleeves and moves until she is standing before Spock and McCoy. "This," she says bluntly, before stepping forward and placing two fingers on each of their foreheads.

McCoy's had a few mindmelds in his time, and this doesn't feel anything like it. It's more like an ice-cream headache – a sharp, jagged pain through his head. It only lasts a few seconds, but that's more than enough.

The ambassador steps away and McCoy rubs his forehead, trying his best not to glare. "What on Earth was that?" he asks.

"That was the start of the test," she replies. "From now on, the two of you will be unable to move more than ten paces away from each other."

All three of them stare at her. "You can't be serious," Kirk says.

She shakes down her sleeves until they cover her hands. "I am completely serious."

"I don't believe this," McCoy mutters under his breath, before turning and striding out of the room.

Or trying to. He stops just inside the doorway, unable to go any further. No matter how hard he tries, his legs refuse to move. He turns around, and his fear and disbelief must be written all over his face.

"Fascinating," Spock murmurs, and McCoy has to fight the urge to slap him. "I am trying to step backwards, away from Doctor McCoy, but my legs are refusing to respond."

Kirk looks from him to McCoy and back, then turns to the ambassador, eyes big and beseeching. "Can't you undo it?" he asks. "They can't perform their jobs like this."

She shakes her head. "The compulsion will wear off only when they have learned to work together without arguing."

McCoy feels his mouth go dry. Arguing is pretty much how he and Spock communicate. At this rate they could be tied together for months. "Please," he finds himself saying. "You can't-"

"Clearly she can," Spock cuts in. McCoy bites back a retort.

Spock steps forward, looking perfectly composed as always, his attention directed solely towards the ambassador. "Is there no other way to break the compulsion?" Spock asks.

She studies them both, and McCoy swears he sees a glint in her eye a second before she answers, "I included a time limit. It will wear off naturally after one Kalazan month."

"How long is that?" McCoy asks.

"Approximately sixteen point four Standard days," Spock tells him.

McCoy relaxes slightly. At least it won't be for months. Still, more than two weeks shackled to the pointy-eared computer is hardly a picnic. He can't imagine getting more than two days in without wanting to shoot himself.

His thoughts are interrupted by the intercom whistling. "Sickbay to Doctor McCoy."

He's at the panel in an instant. "McCoy here. What is it?"

Chapel's voice comes out of the speaker, sounding slightly agitated. "You'd better get down here, Leonard. Lieutenant Barnes has gone into labour."

"Sarah Barnes? But she's not due for another month." He shakes his head. "I'll be right there."

He gets two steps out of the door this time before being pulled up short. He turns and glares at Spock. "I guess you'll have to come with me."

Spock glances at Kirk, who smiles.

"It's okay, Spock," he says. "Go. I'll finish up here."

Spock nods. "Then I shall see you later." He turns and dips his head briefly in the ambassador's direction. "Ambassador."

She returns the gesture. "Commander."

A second later Spock is striding past him, heading for sickbay, and McCoy has to scramble to keep up. "Just stay out of my way and don't touch anything," he says as they reach the turbolift.

"That was my intention, Doctor," Spock replies. "Rest assured that this situation is no more pleasant for me than it is for you."

McCoy scowls. _Pointy-eared bastard._

Sixteen point four days to go.

x x x

Two days later, Lieutenant Barnes is recovering with her new-born daughter, the Kalazan ambassador has returned to her planet, and McCoy is contemplating murder. He finds Spock frustrating enough when they're _not_ forced to spend twenty-four hours a day within sniping distance of each other.

The worst part is the nights. There is no way he's sharing a bed with Spock, and clearly the Vulcan agrees, as his first inclination is to forgo sleep altogether in favour of meditation. Which _sounds_ fine, but is a whole different situation when McCoy wakes up in the middle of the night to a dark, person-shaped shadow lurking in the corner of his quarters. Spock's lucky he didn't have a phaser at hand, is all he can say about that.

The second worst part is the constant touching. Not between him and Spock. God no. Between Spock and Kirk. Any conversation between the two of them is replete with touching; on the arm, the shoulder, the back. And dammit, he knows what that finger-stroking gesture really means. He can't tell if they think he's oblivious or if they just don't care, but the constant displays of affection are beginning to irritate him.

It isn't that he objects to their relationship, per se, it's just that he can't shake the idea that Kirk's going to end up getting hurt. Spock'll do something stupid and thoughtless and Vulcan, and as Kirk's best friend he'll be left to pick up the pieces. It isn't as if it hasn't happened before, after all.

Still, he's counting down the days – fourteen point two! – and managing to keep his temper. Just.

They've fallen into a routine, of sorts; Spock accompanies him in sickbay during his shift, doing what work he can on a PADD or in McCoy's office, then they go to the labs for a few hours where Spock works and McCoy tries to keep from being bored out of his skull. Yeah, he's definitely going to avoid pissing off any more ambassadors after this.

The only good news on the horizon is that they're heading for Wrigley's for shore leave, so he'll only have a few more days of this – three point four, according to Spock, not that he asked – before he gets a break.

Not that he'll get to see any of the _fun_ parts of Wrigley's, of course. It turns out that Kirk and Spock have booked a cottage in the middle of nowhere in an attempt to "get away from it all", and they're not interested in changing their plans. That's another reason to dislike this relationship, McCoy thinks darkly. Time was, he and Kirk would be out there touring the bars, drinking plentifully and admiring pretty women. Not anymore, though.

_And they'll probably be extra affectionate just to rub it in._ He narrows his eyes at Spock, who is too 'fascinated' by whatever experiment he's carrying out to notice. _You two better not try anything… physical while I'm around, or I'm dousing you both with water._

He glares at Spock for a few seconds more, but gives up when the Vulcan shows no signs of noticing him. It's almost as if Spock's forgotten he's even here, and McCoy has the sudden urge to do something loud and illogical to get his attention.

But that's what got them into this whole mess in the first place, so he restrains himself and goes back to logging inventory requests on his PADD. _Just two weeks to go, God help me._

x x x

The cottage isn't so bad, McCoy supposes. Two bedrooms, bathroom, living room, kitchen, even a study. And he has to admit the view is stunning.

He'd still rather be bar-hopping with Scotty, though. Especially when he learns that there being two bedrooms doesn't mean that they'll actually get used. Kirk makes very clear that he intends to sleep in the same bed as his partner – _just sleep, Bones, nothing else_ – and McCoy will just have to accept it. Either he sleeps on the floor on a mattress, or he can take the bed and they'll sleep on the floor, but it quickly becomes clear that those are the only options. McCoy checks the distance between the doorway and the bed several times – still too long, dammit – before grumpily accepting the floor. (He tested the bed earlier. It squeaks.)

Dinner that night is strained, despite Kirk's best attempts at easing the tension. After dinner the three of them watch a film, before retiring to their one bedroom to sleep. McCoy, by now resigned to the situation, sits grumpily outside the bathroom as Spock completes his nightly ablutions, striding past him without a word the moment the door opens.

He takes his time in the bathroom, it being about the only space he can actually have privacy. When he comes out, he finds Kirk and Spock talking in murmurs, their heads close together. He rolls his eyes and clears his throat loudly, snorting inwardly as two heads snap up to look at him.

"Don't mind me," he says. "By all means, carry on with your conversation. I'm sure it's _fascinating_."

His use of the word obviously hits home; Spock raises an eyebrow and Kirk rubs the back of his neck. "Sorry, Bones," he says. "We didn't mean to leave you out of the conversation. We were just discussing what we're going to do tomorrow."

"Oh." He shrugs, temporarily mollified. "So what are we going to do tomorrow?" _Not visit any pleasure houses, that's for damn sure._

"Well," Kirk begins, "according to the woman who rented us the cottage, there're some caves a couple of miles away. I thought we could go and explore."

"I have been trying to talk him out of it," Spock adds.

Ordinarily McCoy would agree with him. Clambering around in caves isn't his idea of a good time, and adding in Kirk the trouble magnet virtually guarantees that things will end badly. But after almost a week of twenty-four seven Vulcan superiority he's prepared to claim that two plus two is five rather than agree with Spock. "Sounds fine to me," he says. "Just don't get us lost."

A grin crosses Kirk's face at his words. "Great! It's settled then." He pats Spock's arm. "Sorry, Spock. Looks like you're outvoted."

"Indeed," Spock replies. His gaze falls on McCoy, and there's the hint of a question in it. McCoy stares back before abruptly turning away and heading over to his mattress, firmly ignoring the voice in the back of his mind that argues he's being petty. They'll go to the caves tomorrow, and Spock will just have to deal with it.

x x x

They set out just after breakfast the next morning. McCoy is too proud to go back on his word, but he does make sure to pack a tricorder and his medical kit along with their food and supplies. He's still a doctor, after all.

It's actually a nice day – warm and sunny with a light breeze to cool them – and McCoy finds himself relaxing for the first time in days. He can see the rock face in the distance, grey against the horizon, and as they get close he can see the cave openings. Nerves and excitement war for dominance in his stomach as he imagines what might be in there, and he wonders if maybe this wasn't such a good idea.

Kirk, on the other hand, seems to have no such misgivings. He strides up to the opening of the biggest cave, then stops and begins rummaging in his bag. A moment later he exclaims in triumph and yanks out a ball of string.

When he begins tying one end of the string to a large rock at the entrance, McCoy figures he might as well ask. "What's with the string, Jim?"

Kirk pauses in his tying and looks up. "It's what I used to do as a kid. This way, if we get lost we can find our way back."

McCoy glances over at Spock to see the Vulcan's eyebrows have disappeared into his hair. "You do not intend to get us lost?"

Kirk finishes tying off the string and stands. "No one _intends_ to get lost, Spock," he says with a laugh. "But no. I'll be good. This is just insurance."

With that, he heads off into the cave, unwinding the string as he goes. McCoy follows, hearing Spock fall into place behind him.

"This is a bad idea," Spock says quietly. McCoy pretends not to hear him.

The light from the entrance gets dimmer and dimmer the further into the cave they get. Soon it is gone altogether, and they are left at the mercy of their flashlights and Kirk's ridiculous ball of string.

"Hey, look," Kirk says suddenly, pointing at the ceiling. "Stalactites."

He sounds genuinely excited, though McCoy hasn't the faintest idea why. Kirk strides forwards to examine a particularly large stalactite – it comes down to his waist – but has only taken a few steps before he gives a startled yell and vanishes.

McCoy hurries forward, flashlight scanning the ground, and quickly discovers the problem. The ground gives way a few feet in front of them, creating a sort of cliff. He peers over the side and sees Kirk lying at the bottom, about ten feet below them.

"You all right, Jim?" he calls.

Kirk's reply sounds as if it's spoken through gritted teeth. "My leg. I think it's broken."

Spock has already started climbing down to him. McCoy follows, trying to remember the climbing lessons they forced on him at the academy. Spock beats him down of course – damn Vulcan is like a monkey – and is kneeling by Kirk's side holding his hand by the time McCoy makes it to the bottom.

The moment he's down, McCoy pulls his pack off and rummages for his tricorder.

Kirk manages a smile when he finally brings it out, though it's tinged with pain. "Can't believe you brought that."

McCoy shrugs, forcing a grin. "My daddy taught me to always be prepared." He runs it over Kirk and studies the readings. "Yep, fracture of the right tibia. No other injuries that I can see, though."

"Great," Kirk grits out with false cheer. "So it's _just_ the broken leg then."

McCoy bites down on the urge to point out that this whole exploration thing was his idea, instead injecting Kirk with a mild painkiller. "Sorry I don't have anything stronger," he says.

Kirk shrugs. "At least it'll take the edge off." He takes in a sharp breath and adds, "Either of you have a communicator?"

"I do," McCoy says, rummaging in his pack. "Spock, get Jim's pack off. Might as well make him comfortable while I find it."

He finds the communicator quickly and glances up in time to see Spock moving Kirk's pack aside and settling Kirk's head into his lap.

McCoy stills for a moment, struck by the Vulcan's gentleness, then gives himself a mental shake and flips the communicator open. He curses under his breath as he's met with nothing but static.

"Something wrong?" Kirk asks.

McCoy hesitates for a second before nodding. "Some kind of interference. I can't get through."

Spock begins digging through his own pack, being careful not to jostle Kirk. "Allow me to try."

But Spock's communicator encounters the same problem, as does Kirk's.

"Must be something about the rocks," Kirk speculates. It's hard to tell in the dim light, but he seems to have gone pale. McCoy quickly strips off his own coat and covers Kirk with it, hoping he isn't going into shock.

"It'll be fine," he says, trying to keep Kirk's spirits up. "Spock can go for help and-"

"Doctor," Spock interrupts quietly, and McCoy goes silent as realisation dawns. Of _course_ Spock can't go for help. Not unless they both go, and someone has to stay with Kirk.

"I will attempt to adapt my communicator," Spock says, in the silence that follows. "Perhaps I can break through the interference."

"Yeah," McCoy says hoarsely, as the full scope of their situation begins to sink in. "You do that."

Kirk's breathing becomes steadily harsher as Spock works on the communicator, his face etched with pain. As McCoy suspected, the hypo has barely taken the edge off. He glances at Spock, who is hard at work, all his concentration focused on restoring their link to the outside world. To McCoy's eyes he doesn't seem to be making any progress at all, but he doesn't voice that thought.

He's considering giving Kirk another shot of painkillers when Kirk digs his teeth into his bottom lip and then says, in a voice barely above a whisper, "Spock, please."

Spock pauses in his work, looking down at Kirk. "You are certain?"

Kirk gives a shaky laugh. "God yes."

McCoy frowns. He hates when they do that talking-without-words thing. Gives him the creeps.

As he watches, Spock presses two fingers to Kirk's temple. A second later Kirk's eyes slip closed and his entire body goes slack.

McCoy is on his feet in an instant. "What the hell did you do to him?" he asks.

Spock looks up at him, expression infuriatingly calm. "He is not injured, Doctor." He tilts his head and corrects, "Not further injured, at least. I merely instructed his system to take him into sleep. It seemed more humane than leaving him to suffer."

Scowling, McCoy grabs his tricorder and kneels down next to Kirk, scanning him quickly. Spock's word checks out; the readings show that Kirk is in the early stages of sleep.

He looks up, a sarcastic comment on his lips, but what he sees makes the words stick in his throat. Spock is watching Kirk sleep, one hand brushing gently through his hair. His expression is oddly soft, and McCoy finds himself wondering if maybe he's misjudged Spock. If this is the side of him that Kirk sees, maybe their relationship isn't so strange after all.

"You really love him, don't you?" he says softly.

Spock doesn't look up, fingers still stroking through Kirk's hair. "You doubted it?" He sounds honestly curious.

"Yeah," McCoy admits. "After you left him the first time, I thought-" He cuts himself off. For once in their lives he and Spock are communicating without insults, and he doesn't want to ruin that. "Well, it doesn't matter what I thought. I was wrong."

"You thought that I would hurt him again," Spock says. He draws in a breath, fingers stilling. "It is an understandable concern, given my past actions, but you need not worry. I will not leave him again."

"I believe you," McCoy says. He clears his throat and adds, "For what it's worth, I'm sorry I got us into this mess."

Spock finally meets his eyes. "You were not the only one at fault, Leonard. I will accept your apology if you will accept mine."

McCoy can count the number of times Spock has actually used his name on one hand. It's a clear olive branch, and he smiles. "Deal."

He looks back down at Kirk and decides to give the two of them a few moments of privacy, such as it is. "I'm going to look around a bit," he says, rising carefully to his feet. "See if I can find something to splint Jim's leg with."

Spock merely nods. A week ago, that would have annoyed him. Now, McCoy just gives him another smile before turning and shining his flashlight over the ground. It may have just been an excuse, but if by any chance he _can_ find something to use as a splint, it'll be a big help.

He walks forward, scanning the floor, walls, even the ceiling. Aside from stalagmites and stalactites there doesn't seem to be much of anything. He stops, shining his flashlight forward into the darkness, then sighs and turns around to go back to Kirk and Spock.

He frowns when he sees them. They're further away than he'd expected. His heart clicks into high gear as he begins walking towards them, counting every step. _Eight, nine, ten._

He stops, mouth dry, still a good four or five steps away from Spock, who is back working on the communicator.

Spock glances up at him, raising an eyebrow. "Doctor? Is something wrong?"

"Not wrong, exactly," McCoy says, heart pounding in his chest. He holds up a hand as Spock begins to answer, adding, "Just shut up and let me check something." He steps forwards until he is at Spock's side, then turns and takes a step forward. "One." He continues walking, counting the steps out loud as he goes. "Two. Three. Four. Five. Six. Seven. Eight. Nine. Ten." He hesitates, swallowing hard, then steps forward. "Eleven." Joy and relief rush through him as he continues, "Twelve. Thirteen."

He makes it to fifteen before turning and making his way back. Spock looks about as shocked as he feels, eyebrows disappearing into his hair. "The compulsion is broken," he says.

McCoy nods, grinning. "She told us it'd break when we learned to work together." If Spock weren't, well, _Spock_, McCoy thinks he would hug him. They're _free_.

He's pretty sure Spock realises what this means at the same moment he does, as he immediately begins shifting himself out from under Kirk's head. "I will go for help," Spock says once he is free, Kirk's head now resting on his discarded pack. He glances down, a brief hint of emotion coming into his face. "You will take care of him?"

"Of course," McCoy promises. "Now get out of here."

Spock nods, then shimmies up the wall and is out of sight within moments.

For lack of anything better to do, McCoy goes to sit by Kirk. "You're going to kick yourself later, Jim," he says quietly. "Me and the hobgoblin finally see eye-to-eye on something, and you miss it."

The only response is Kirk's breathing, deep and even. With a sigh, McCoy leans against the wall and settles in to wait.

x x x

Spock returns with a rescue team within half an hour, and with their help Kirk is soon out of the cave and on his way to the hospital. Spock and McCoy go with him.

The paramedics are initially concerned by Kirk's unconscious state, but once Spock explains his actions they seem almost impressed, and McCoy surprises himself by feeling an odd sense of pride in his one-time enemy. Spock, for his part, seems immune to the praise, his entire focus on the unconscious human who is the topic of their conversation.

Looking at him now, McCoy wonders how he could have thought that Spock didn't really love Kirk. Residual anger, he suspects, for having to pick up the pieces the first time Spock left. It's only now that he's realising something that Kirk must have realised months ago – that this Spock isn't the same one who left for Gol and broke Kirk's heart. Melding with V'Ger changed him, made him warmer, less distant.

He's still a pain in the ass, of course, but now that McCoy thinks about it, even that has changed. Being tied to Spock is still pretty high up on his list of unpleasant experiences, but if something like this had happened during the first mission he honestly believes one of them would have gone mad by now. They managed a whole six days in each other's company, twenty-four seven, and didn't kill each other. It's progress, of a sort.

It doesn't take long for the doctors to set Kirk's leg and knit the bone back together. They keep him under for the procedure – it isn't strictly necessary, but as he's already asleep they see no reason to wake him – and it's a good two hours afterwards before he wakes up.

Spock is sitting in a chair, supposedly meditating, but from where McCoy's standing it looks a lot like he's staring at Kirk. McCoy is on the verge of asking him to do his Vulcan mumbo jumbo and just wake Kirk up already, when there's a voice from the bed. "Hey."

McCoy's head snaps up to see Kirk smiling tiredly at them. "Jim," Spock breathes, and is at Kirk's side in an instant.

Kirk holds out a hand to him, and Spock takes it. "Don't look so worried," Kirk says. "I broke my leg, I'm not dying." He wiggles his toes experimentally. "Besides, it's all fixed now anyway."

"It'll be weak for the next few days, though," McCoy warns. "So no strenuous exercise."

Kirk snorts. "Don't worry. I don't plan on exploring any more caves. Believe me, I've learned my lesson."

Spock clears his throat. "If it helps, Jim, your string idea did end up assisting me when I went to find help."

A faint smile crosses Kirk's face. "Really?"

Spock nods. "I do not believe I could have returned so quickly if it had not been there to guide me."

McCoy has his suspicions about whether that's the whole truth, but as Kirk seems to have cheered up at the thought he's willing to let it slide. For now, anyway.

Kirk shifts against his pillows, seemingly making himself more comfortable. A frown crosses his face, and McCoy wonders if he's in pain. But the source of Kirk's frown is made apparent when he asks, "Wait a minute, how did you go for help? I thought you were trying to fix the communicator." His frown deepens as he adds, "Did the two of you just leave me there alone?"

"Ah," Spock says. "I forgot that you did not know. The compulsion is broken."

Kirk sits bolt upright. "What?"

He grimaces suddenly, and McCoy is pretty sure _that's_ a sign of pain. "Lie back before you hurt yourself," he grumbles, pushing Kirk back against the pillows.

Kirk obeys, looking between them with an expression of equal parts amazement and disbelief. "You broke the compulsion? How? I don't think I've ever seen you two agree on anything."

"We agree on you," Spock replies quietly. "The doctor and I both care for you, Jim, and our attempts to help you allowed us to reach a new understanding of each other."

Kirk beams. "And this isn't just a temporary thing, right?" he asks. "You're not going to go back to being at each other's throats the minute I'm better?"

McCoy shrugs. "Can't promise anything, Jim. Most likely the hobgoblin and I will still have our little spats, but I think I understand a little better what makes him tick."

He notices Kirk's attention begin to stray, and shakes his head with a smile. "And on that note," he says, "I'm going to go get some coffee and enjoy being _alone_ for a while. You two lovebirds have fun."

Kirk drags his eyes away from Spock long enough to give him a smile and a, "See you later, Bones."

Spock adds, "Farewell, Doctor," but he sounds slightly distracted. And from the way his fingers are laced through Kirk's, McCoy thinks he has a fairly good idea why.

He rolls his eyes, but it's in a good-natured, teasing way. "Just don't do anything that's going to aggravate his injury," he says, and leaves the room before they can respond.

He whistles as he makes his way to the cafeteria, basking in the sensation of finally being alone with his thoughts. He pulls out his communicator, intending to contact Scotty, and then pauses, tapping in a quick message to Spock. _Lunch tomorrow. You, me, Jim. You in?_

The response comes a few minutes later; a single word. _Indeed._

McCoy shakes his head with a smile. It isn't much, but it's a start.

He wonders what the Kalazan ambassador would say to that.


End file.
